There is a strong demand to reduce the size of electronic systems. The size reduction is especially desirable in mobile electronic devices in which the space is a premium, but is also desirable in servers that are placed in big data centers since it is important to squeeze in as many servers as possible in a fixed real estate.
One of the largest components in electronic systems is a voltage regulator (also referred to as a power regulator). A voltage regulator can include a semiconductor chip, such as a DC-DC regulator chip, that delivers voltage from a voltage source (e.g., a battery) to an output load. The output load can include a variety of integrated chips (e.g., an application processor, a processor, a memory device, such as a dynamic read access memory (DRAM) and a NAND flash memory, radio-frequency (RF) chips, WiFi combo chips, and power amplifiers) in an electronic device. Unfortunately, a voltage regulator can include many bulky electronic components. Since each integrated chip may need a dedicated voltage regulator, it is desirable to reduce the size of the voltage regulators in electronic systems.
A voltage regulator can include a switched-inductor regulator. A switched-inductor regulator transfers charges from the power source to the output load using an inductor. A switched-inductor regulator can use power switches to connect/disconnect the inductor to one of multiple voltages, and provide an output voltage that is a weighted average of the multiple voltages. A switched-inductor regulator can adjust the output voltage by controlling the amount of time the inductor is coupled to one of the multiple voltages.
Unfortunately, a switched-inductor regulator is often not suitable for highly integrated electronic systems. The conversion efficiency of a switched-inductor regulator depends on the quality and size of the inductor, in particular when the power conversion ratio is high and when the amount of current consumed by the output load is high. Because an inductor can occupy a large area and is bulky to integrate on-die or on-package, existing switched-inductor regulators often use a large number of off-chip inductor components. This strategy often requires a large area on the printed circuit board, which in turn increases the size of the electronic device. The challenge is exacerbated as mobile system-on-chips (SoCs) become more complex and need increasingly larger number of voltage domains to be delivered by the voltage regulator.